Enhanced Piezoelectricity of MAPbI<sub>3</sub> by the Introduction of MXene and Its Utilization in Boosting High-Performance Photodetectors.

Han, Gaosi; Li, Xiao-Fen; Berbille, Andy; Zhang, Yueming; Luo, Xiongxin; Liu, Lindong; Li, Longyi; Wang, Zhong Lin et al. · Adv Mater · 2024

basic_science · Level V

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Abstract

Recently, perovskite photodetectors (PDs) are risen to prominence due to substantial research interest. Beyond merely tweaking the composition of materials, a cutting-edge advancement lies in leveraging the innate piezoelectric polarization properties of perovskites themselves. Here, the investigation shows utilizing Ti<sub>3</sub>C<sub>2</sub>T<sub>x</sub>, a typical MXene, as an intermediate layer for significantly boosting the piezoelectric property of MAPbI<sub>3</sub> thin films. This improvement is primarily attributed to the enhanced polarization of the methylammonium (MA<sup>+</sup>) groups within MAPbI<sub>3</sub>, induced by the OH groups present in Ti<sub>3</sub>C<sub>2</sub>T<sub>x</sub>. A flexible PD based on the MAPbI<sub>3</sub>/MXene heterostructure is then fabricated. The new device is sensitive to a wide range of wavelengths, displays greatly enhanced performance owing to the piezo-phototronic coupling. Moreover, the device is endowed with a greatly reduced response time, down to millisecond level, through the pyro-phototronic effect. The characterization shows applying a -1.2% compressive strain on the PD leads to a remarkable 102% increase in the common photocurrent, and a 76% increase in the pyro-phototronic current. The present work reveals how the emerging piezo-phototronic and pyro-phototronic effects can be employed to design high-performance flexible perovskite PDs.